Leviticus 23:24

23:24 “Tell the Israelites, ‘In the seventh month, on the first day of the month, you must have a complete rest, a memorial announced by loud horn blasts, a holy assembly.

Numbers 29:1

Blowing Trumpets

29:1 “‘On the first day of the seventh month, you are to hold a holy assembly. You must not do your ordinary work, for it is a day of blowing trumpets for you.